The commander of NATO-led operations that helped Libyan rebels overthrow Moammar Gadhafi took over Friday as the top U.S. military commander in Asia and the Pacific.

Adm. Samuel Locklear moved into the job leading the Pacific Command as the United States places greater emphasis on its military presence in the region in response to Asia's growing economic importance and China's rise as a military power.

"In a world where the economy, population and military power are all shifting toward the Pacific, the job you fill today has never been more important," Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said at a change-of-command ceremony.

America's future depends on the peace and prosperity of Asia and the Pacific, Defense Secretary Leon Panetta told the crowd of several hundred people gathered at command headquarters on a hill overlooking Pearl Harbor.

"When I look across the world to the threats and challenges that we face as a nation — from terrorism, natural disasters, proliferation of weapons of nuclear destruction, to rogue nations and the rising powers of the Pacific — this region has most of those threats here," Panetta said.

Panetta said the position required not just a great warrior but also "a great diplomat."

Locklear last month told the Senate Armed Services Committee at his confirmation hearing that China's military buildup is a source of strategic uncertainty. He described the current military relationship as "cooperative but competitive."

"It would be my plan to, in every way possible, improve our military-to-military relationship, with the recognition that there are things we won't agree on, that greater transparency is for the good of all of us to avoid miscalculation," Locklear told the committee.

Willard, the outgoing commander, has said that U.S.-China military ties have been maintained at a senior level but China is reluctant to have tactical and operational ties with the U.S.

In the past, Beijing has stymied bilateral military exchanges in response to U.S. arms sales to the self-governing island of Taiwan, which China considers a renegade province.

Panetta said Locklear brings "great talents" to his new job, and praised the admiral's performance during the campaign against Gadhafi's forces. He noted some questioned the success of that operation.

"Bringing that many nations together to go after targets in Libya and be able to coordinate that, to develop targets and then distribute those targets to various countries — that's a huge responsibility," Panetta said Thursday. "And yet, Sam Locklear was able to put that operation together."

Locklear graduated from the U.S. Naval Academy in 1977. He has commanded the U.S. 3rd Fleet and the Nimitz aircraft carrier strike group. Most recently he commanded U.S. Navy in Europe and Africa.

The Pacific Command is responsible for an area stretching from the U.S. West Coast to India. It oversees some 325,000 military and civilian personnel — about one-fifth of the military's payroll.